My apologies to the moderator for such a long post, but I have some information to share on the Graflex Strobomatic 500 (or Strob 500) Flash system that might be of some help to both the newcomer to the Graflex system and those who might wish to purchase a Graflex flash system and need information on what to look for (or ask for).

For the newcomer, please excuse my use of the present tense in lieu of the past tense, as Graflex has been out of business for over 30 years now and the Strob 500 is not being made anymore, and any Strob 500 outfit's you might find have seen usage from rarely used to roughly used, so beware, and let their condition be your guide as to whether you wish to purchase one at the price asked for.

The Strob 500 Power Base's (lower half) comes in three different configurations:

(1) Strob 500 AC Power Base (lower half) uses a 20 foot cord for AC wall (or mains current) 117 VAC current (at the time, now most current is 120 to 125 VAC).

(3) Strob 500 RG Power Base (lower half), the MOST desirable power base, uses an internal circuit board that takes power from a removable plastic case that holds Eight ( 1.2 VDC "D" Ni-Cad Cells (usually 1600 mAh) in series for a total of 9.6 VDC and is charged with a 120 VAC to 12 volt VDC wall transformer.

The earlier (older) Power Base's (lower half) has the logo "Strobomatic 500" stamped along the top edge of the case with the power type after the "Strobomatic 500" as in AC - HV - RG, and in the lower right corner of the power base there is a round raised logo that shows the Graflex lower case "+g" trademark.
The newer Power Base's (lower half) has the logo "Singer" (alone by itself on the left) then "Graflex" (top line on the right) and then "Strob 500" (bottom line on the right) on a metal foil label along the top edge of the case and in the lower right corner of the power base there is a round raised logo that shows the power type, as in AC (Yellow background), HV (Blue??? background) and the RG (Red background).

I also have 2 AC Power Base's (lower half) that have a metal foil label along the top edge of the case that says "Graflite" (alone by itself on the left) and with a yellow background that says "Strob 500" in a single line, and also in the lower right corner of the power base there is a round raised logo that shows the power type of AC (Yellow background), the Yellow background style is also used on another Power Base that I have that is a RG model and perhaps on the HV Model also.

The earlier (older) Control Head's (top half) did not have a metal foil label on the top of the Capacitor Pack case, but did have the corresponding icon's on the top of the Control Head for the OFF, ¼ , ½ and FULL power levels.

The newer Control Head (top half), which contains the (4) four 500 WVDC, 490 microfarad, Aluminum Electrolytic capacitor's, has the logo "Graflex General Precision" (as two lines, on the left side of the label) then "Strobomatic 500" (on the right side of the label) on a metal foil label on the top of the Capacitor Pack case, along with the power level switches (Black = OFF, White = ¼ Power, Yellow = ½ Power and Red for FULL power) on the top front of the Control Head case, along with the corresponding icon's on the top of the Control Head for the OFF, ¼ , ½ and FULL power levels.

Also I should mention that capacitors, by their very nature and construction, are prone to drying out in older years and have a tendency to start shorting out internally, hence the crackling that some have heard when using their Strob 500 Outfit's, sadly to my dismay (and experience) the only real way to deal with this is to test the capacitors with a Volt & Ohm meter to ascertain the shorting capacitor and to replace it with a reliable capacitor, and so far I have not been able to find a vendor that can supply me with an identical capacitor in the correct physical and electrical specifications.

I might also mention some notes about the Strob 500 flash heads, as there also seems to be some important configurations in these also:

(1) Model #???? (may also be a Model #2241) - An all Black Rear housing with a Gray front, marked with "Graflite" above the red open flash button and "Strob 500" below the red open flash button, along with "Made in USA by Lenzar Optics Corp. this flash head has only a flash to subject distance flash calculator dial, a neon ready light that is protrudes from the flash head surface in a clear rounded dome, it does not have the built-in slave feature with a Slave/Sync slide switch.

(2) Model #2241 - All Black Rear housing with a Silver panel on the very back and a Gray front, and below the red open flash button is marked with "Graflex/General Precision" (on 2 lines, one over the other) and also "STROBOMATIC", this model also has a built-in slave feature with a Slave/Sync slide switch on the bottom right of the rear silver panel that also contains a flash to subject distance flash calculator dial, and a neon ready light that is almost flush with the flash head surface.